Firearms are usually equipped with fixed sights, typically a front sight and a rear sight. In handguns, such as auto-loading pistols, a slide runs from the front of the pistol over the barrel to the back of the pistol over the receiver, and it reciprocates when the gun fires, sliding rearward just after firing the gun and then sliding forward to chamber a new round of ammunition and reset the fire control system.
In recent years, optical gun sights have been improved through developments such as reductions in their size, weight, and improved energy efficiency to the point that it is now practical to affix them to the slide of auto-loading pistols in addition to other firearm types. The ability of the user to hit a target depends in part on the user's ability to aim accurately. An improved gun sight may improve the user's ability to aim when the gun is fired.
These improved gun sights include reflex or holographic sights. They use lenses and projected light to produce a red dot or other aiming indicator superimposed on an image of the target visible in the optical viewfinder that indicates where a bullet would strike the target if the gun fires at that moment. The target does not have a red dot on it; the sight makes it appear so in the viewfinder.
Optical sights may be used with pistols by mounting them to the slide. Because the slide reciprocates after firing, and does so rapidly, the attachment of the optical sight to the slide should be secure. Some handguns have an optical sight in place of the rear sight and the integral nature of that type of attachment helps to assure a secure connection.
Some handguns provide a place for the attachment of a particular optical sight. Here, too, the type of attachment, although designed for removability, is still relatively secure because the gun receives a particular, removable optical sight.
Also, a gunsmith may be hired to modify an existing pistol so that it will receive a particular optical sight.
As improvements continue in optical sight technology, and better sights become available, there is a need for a system that enables owners to mount any improved optical sights that may become available from different manufacturers to the user's pistol and do so securely.
One common solution for this need is the use of a “cut” or flat area formed on the top surface of the slide of a pistol that receives an adaptor plate. An adaptor plate corresponds to an optical sight, and provides the interface for the gun to receive that optical sight. A different adaptor plate is required to adapt a different optical sight to that gun. Screws attach the optical sight to the adaptor plate and to the slide below it. This method offers versatility but lacks the security of a direct mounting solution and places the optical sight higher above the slide than a direct mounting solution making co-witness with the existing sights difficult.
A better way of removably attaching an after-market optical sight to the slides of automatic pistols would be an advantage.